<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>绝对定位</title>
</head>
<style>
    div{
        width: 100px;
        height: 100px;
    }

    .box01{
        float: left;
        background-color: red;
    }

    .box02{
        float: left;
        background-color: green;
    }

    .box03{

        height: 200px;
        background-color: orange;
    }
</style>

<body>
    <div class="box01"></div>
    <div class="box02"></div>
    <div class="box03">123</div>
</body>
</html>